Fine-needle aspiration findings in nodular myositis: a case report

Fine-needle aspiration (FNA) is frequently the initial diagnostic modality for the workup of suspected metastatic disease in subcutaneous or deeper soft tissues. The technique is less well-accepted for the diagnosis of primary soft-tissue lesions. Occasionally during the investigation of suspected metastatic disease, primary processes of the soft tissues will undergo FNA. Thus, familiarity with the cytomorphology of soft-tissue reparative and neoplastic lesions is important. A variety of reparative and degenerative entities exist within the soft tissues, one of which is localized nodular myositis. This lesion may be a precursor of generalized polymyositis, including polymyositis associated with graft vs. host disease, or it may remain a localized process. Aspirates from localized nodular myositis demonstrate fragments of striated muscle including degenerating and regenerative myocytes, a mixed inflammatory background, and necrotic debris. Cytologic identification of this lesion can be therapeutically important, particularly in post-bone marrow transplant patients.